Apparatus for and method of including a packer to facilitate anchoring a first conduit to a second conduit

ABSTRACT

Apparatus and methods are disclosed for anchoring a first conduit to a second conduit. The first conduit is typically an expandable conduit whereby at portion of the first conduit is expanded by applying a radial force thereto to provide an anchor and/or seal between the first and second conduits. An inflatable device is provided that can be used to provide a temporary anchor while the first (expandable) conduit is radially expanded. An expander device that is capable of applying a radial expansion force to the first conduit is optionally attached to the inflatable device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase application of PCTInternational Application No. PCT/GB00/03406, filed. Sep. 6, 2000.

FIELD OF THE INVENTION

The present invention relates to an apparatus for and a method ofanchoring a first conduit to a second conduit, the apparatus and methodparticularly, but not exclusively, using an inflatable device to providea temporary anchor.

BACKGROUND OF THE INVENTION

A borehole is conventionally drilled during the recovery of hydrocarbonsfrom a well, the borehole typically being lined with a casing. Casingsare installed to prevent the formation around the borehole fromcollapsing. In addition, casings prevent unwanted fluids from thesurrounding formation from flowing into the borehole, and similarly,prevents fluids from within the borehole escaping into the surroundingformation.

Boreholes are conventionally drilled and cased in a cascaded manner;that is, casing of the borehole begins at the top of the well with arelatively large outer diameter casing. Subsequent casing of a smallerdiameter is passed through the inner diameter of the casing above, andthus the outer diameter of the subsequent casing is limited by the innerdiameter of the preceding casing. Thus, the casings are cascaded withthe diameters of the casing lengths reducing as the depth of the wellincreases. This gradual reduction in diameter results in a relativelysmall inside diameter casing near the bottom of the well that couldlimit the amount of hydrocarbons that can be recovered. In addition, therelatively large diameter borehole at the top of the well involvesincreased costs due to the large drill bits required, heavy, equipmentfor handling the larger casing, and increased volumes of drill fluidthat are required.

Each casing is typically cemented into place by filling cement into anannulus created between the casing and the surrounding formation. A thinslurry cement is pumped down into the casing followed by a rubber plugon top of the cement. Thereafter, drilling fluid is pumped down thecasing above the cement that is pushed out of the bottom of the casingand into the annulus. Pumping of drilling fluid is stopped when the plugreaches the bottom of the casing and the wellbore must be left,typically for several hours, whilst the cement dries. This operationrequires an increase in rig time due to the cement pumping and hardeningprocess, that can substantially increase production costs.

It is known to use a pliable casing that can be radially expanded sothat an outer surface of the casing contacts the formation around theborehole. The pliable casing undergoes plastic deformation whenexpanded, typically by passing an expander device, such as a ceramic orsteel cone or the like, through the casing. The expander device ispropelled along the casing in a similar manner to a pipeline pig and maybe pushed (using fluid pressure for example) or pulled (using drillpipe, rods, coiled tubing, a wireline or the like).

Lengths of expandable casing are coupled together (typically by threadedcouplings) to produce a casing string. The casing string is insertedinto the borehole in an unexpanded state and is subsequently expandedusing the expander device, typically using a substantial force tofacilitate the expansion process. However, the unexpanded casing stringrequires to be anchored either at or near an upper end or a lower endthereof during the expansion process to prevent undue movement. This isbecause when the casing string is in an unexpanded state, an outersurface of the casing string does not contact the surrounding boreholeformation or an inner face of a pre-installed casing or liner (until atleast a portion of the casing has been radially expanded), and thusthere is no inherent initial anchoring point.

Slips are conventionally used to temporarily anchor the unexpandedcasing to the borehole during the expansion process. Slips are generallywedge-shaped, steel, hinged portion that provide a temporary anchor whenused. Slips are actuated whereby the wedge-shaped portions engage withthe surrounding borehole formation or a casing or liner.

However, the mechanical configuration of slips often causes damage tothe casing or liner. In some cases, the damage causes the slip to faildue to a loss of mechanical grip. Slip-type devices in open-holeengaging formation are often prone to slippage also.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedan apparatus for anchoring a first conduit to a second conduit, theapparatus comprising an inflatable device for engaging with the firstconduit, wherein the inflatable device is inflatable to facilitateanchoring of the first conduit to the second conduit.

According to a second aspect of the present invention, there is provideda method of anchoring a first conduit to a second conduit, the methodcomprising the steps of providing a first conduit, providing aninflatable device in contact with the first conduit, running thefirst-conduit and inflatable device into the second conduit, andsubsequently inflating the inflatable device to facilitate anchoring ofthe first conduit to the second conduit.

According to a third aspect of the present invention, there is provideda method of anchoring an expandable conduit to a second conduit, themethod comprising the steps of providing an expandable conduit, runningthe first conduit into the second conduit, passing an inflatable deviceinto the conduit, and subsequently inflating the inflatable device tofacilitate anchoring of the expandable conduit to the second conduit.

The first conduit is typically an expandable conduit.

The first or expandable conduit may comprise any type of expandableconduit that is capable of sustaining plastic and/or elasticdeformation. The first conduit typically comprises an expandable liner,casing or the like. The second conduit may comprise any type of conduit.The second conduit typically comprises a liner, casing, borehole or thelike.

The inflatable device typically comprises an inflatable balloon-typeportion coupled to a ring. This allows a string or the like to be passedthrough the inflatable device in use.

Optionally, the inflatable device includes an expander device. Theexpander device is optionally telescopically coupled to the inflatabledevice, so that when the expander device is moved a certain distance,the inflatable device is deflated and subsequently moves with theexpander device.

Alternatively, the expandable device may be releasably attached to theinflatable device, typically using a latch mechanism.

The inflatable device may be located within the expandable conduit.Alternatively, the inflatable device may be coupled at or near an upperend of the expandable conduit, or at or near a lower end of theexpandable conduit. The inflatable device may be coupled to theexpandable conduit using any suitable connection.

The inflatable device is typically inflated to expand the expandableconduit whereby the expandable conduit contacts the second conduit,thereby providing an anchor. In this embodiment, the expandable conduitis optionally provided with a slotted portion to facilitate expansion.This is advantageous as the contact between the expandable conduit andthe second conduit provides the anchor, and forces applied to theexpandable conduit are mainly channelled into the second conduit via theexpandable conduit and not the inflatable device.

Alternatively, the inflatable device is inflated whereby a portionthereof directly contacts the second conduit to provide an anchor.

The expander device is typically manufactured from steel. Alternatively,the expander device may be manufactured from ceramic, or a combinationof steel and ceramic. The expander device is optionally flexible.

The expander device is optionally provided with at least one seal. Theseal typically comprises at least one O-ring.

The method optionally comprises one, some or all of the additional stepsof inserting an expander device into the expandable conduit, operatingthe expander device to expand the expandable conduit, deflating theinflatable device, and removing the expander device and/or theinflatable device from the expandable conduit and/or the second conduit.

The method optionally comprises one, some or all of the additional stepsof attaching an expander device to the inflatable device, operating theexpander device to expand the expandable conduit, re-attaching theexpander device to the inflatable device, deflating the inflatabledevice, and removing the expander device and/or the inflatable devicefrom the expandable conduit and/or second conduit.

The expander device is typically operated by propelling it through theexpandable conduit using fluid pressure. Alternatively, the expanderdevice may be operated by pigging it along the expandable conduit usinga conventional pig or tractor. The expander device may also be operatedby propelling it using a weight (from the string for example), or may bypulling it through the expandable conduit (e.g. using drill pipe, rods,coiled tubing, a wireline or the like).

Optionally, the inflatable device may act as a seal whereby fluidpressure can be applied below the seal.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention shall now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIGS. 1 a to 1 d are successive stages in anchoring and expanding anexpandable conduit within a second conduit using a first embodiment ofan inflatable device;

FIGS. 2 a to 2 d are successive stages in anchoring and expanding anexpandable conduit within a borehole to tie back the expandable conduitto a casing using a second embodiment of an inflatable device;

FIGS. 3 a to 3 d are successive stages in anchoring and expanding anexpandable conduit within a second conduit using a third embodiment ofan inflatable device;

FIG. 4 a is a front elevation showing a first configuration of afriction and/or sealing material that can be applied to an outer surfaceof the conduits shown in FIGS. 1 to 3;

FIG. 4 b is an end elevation of the friction and/or sealing material ofFIG. 4 a;

FIG. 4 c is an enlarged view of a portion of the material of FIGS. 4 aand 4 b showing a profiled outer surface;

FIG. 5 is a schematic cross-section of an expandable conduit that can beused with the present invention having an alternative configuration of afriction and/or sealing material;

FIG. 6 a is an front elevation of the friction and/or sealing materialof FIG. 5; and

FIG. 6 b is an end elevation of the friction and/or sealing material ofFIG. 6 a.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, there is shown in sequence (FIGS. 1 a to 1 d)successive stages of anchoring an expandable conduit 10 to a casing 12provided in a borehole (not shown), the borehole typically being drilledto facilitate the recovery of hydrocarbons. The expandable conduit 10 istypically an expandable liner or casing, but any type of expandableconduit may be used.

The borehole is conventionally lined with casing 12 to prevent theformation around the borehole from collapsing and also to preventunwanted fluids from the surrounding formation from flowing into theborehole, and similarly, prevents fluids from within the boreholeescaping into the surrounding formation. It should be noted that thecasing 12 may comprise any type of conduit, such as a pipeline, a liner,a casing, a borehole or the like.

An inflatable device 14, that in this embodiment has an expander device16 telescopically attached thereto, is positioned within the expandableconduit 10 before the conduit 10 is inserted into the casing 12.

Referring to FIG. 1 a, the conduit 10 with the inflatable device 14 andexpander device 16 located therein is run into the hole to the requiredsetting depth. As can be seen in FIG. 1 a, a lower end 10 l of theexpandable conduit 10 is radially expanded (indicated generally at 18)to allow the inflatable device 14 and the expander device 16 to belocated therein. It will be appreciated that although FIGS. 1 a to 1 dshow the inflatable device 14 and expander device 16 located at or nearthe lower end 10 l of the conduit 10, the inflatable device 14 and/orthe expander device 16 may also be located at or near an upper end ofthe conduit 10. In this case, the expander device 16 is propelleddownwardly using, for example, the weight of a string, fluid pressure orany other conventional method.

The inflatable device 14 may be of any suitable configuration, but istypically a device that has an inflatable annular balloon-type portion14 b that is mounted on an annular ring 14 r. The annular ring 14 rallows a string, wireline or the like to be passed through theinflatable device 14 as required. This is particularly advantageouswhere the inflatable device 14 is positioned at the upper end of theconduit 10. Thus, substantially full-bore access is still possible.

Referring to FIG. 1 b, the inflatable device 14 is inflated to expandthe inflatable annular balloon-type portion 14 b. As the balloon-typeportion 14 b expands, an anchor portion 10 a of the conduit 10 is alsoexpanded. The anchor portion 10 a is expanded by the inflatable device14 until it contacts the casing 12, as shown in FIG. 1 b. This contactbetween the anchor portion 10 a of the expandable conduit 10 and casing12 provides an anchor point and/or a seal between the expandable conduit10 and the casing 12. The outer surface of the anchor portion 10 a maybe suitably profiled (e.g. ribbed) or coated with a friction and/orsealing material 100 (FIGS. 4 a to 4 c) to enhance the grip of theconduit 10 on the casing 12. The friction and/or sealing material 100may comprise, for example, any suitable type of rubber or otherresilient materials. It should be noted that the friction and/or sealingmaterial 100 can be provided on an outer surface 10 s of the conduit 10at various axially spaced-apart locations.

Referring to FIGS. 4 a to 4 c, the friction and/or sealing material 100typically comprises first and second bands 102, 104 that are axiallyspaced apart along a longitudinal axis of the conduit 12. The first andsecond bands 102, 104 are typically axially spaced by some distance, forexample 3 inches (approximately 76 mm).

The first and second bands 102, 104 are preferably annular bands thatextend circumferentially around the anchor point 10 a of the conduit 10,although this configuration is not essential. The first and second bands102, 104 typically comprise 1 inch wide (approximately 25.4 mm) bands ofa first type of rubber. The friction and/or sealing material 100 neednot extend around the full circumference of the conduit 10.

Located between the first and second bands 102, 104 is a third band 106of a second type of rubber. The third band 106 preferably extendsbetween the first and second bands 102, 104 and is thus typically 3inches (approximately 76 mm) wide.

The first and second bands 102, 104 are typically of a first depth. Thethird band 106 is typically of a second depth. The first depth isoptionally larger than the second depth, although they are typically thesame, as shown in FIG. 4 a. The first and second bands 102, 104 mayprotrude further from the surface 10 s than the third band 106, althoughthis is not essential.

The first type of rubber (i.e. first and second bands 102, 104) ispreferably of a harder consistency than the second type of rubber (i.e.third band 106). The first type of rubber is typically 90 durometerrubber, whereas the second type of rubber is typically 60 durometerrubber. Durometer is a conventional hardness scale for rubber.

The particular properties of the rubber may be of any suitable type andthe hardnessess quoted are exemplary only. It should also be noted thatthe relative dimensions and spacings of the first, second and thirdbands 102, 104, 106 are exemplary only and may be of any suitabledimensions and spacing.

As can be seen from FIG. 4 c in particular, an outer face 106 s of thethird band 106 can be profiled. The outer face 106 s is ribbed toenhance the grip of the third band 106 on an inner face 12 i of thecasing 12. It will be appreciated that an outer surface on the first andsecond bands 102, 104 may also be profiled (e.g. ribbed).

The two outer bands 102, 104 being of a harder rubber provide arelatively high temperature seal and a back-up seal to the relativelysofter rubber of the third band 106. The third band 106 typicallyprovides a lower temperature seal.

Referring to FIG. 5, there is shown an alternative conduit 120 that canbe used in place of conduit 10. Conduit 120 is substantially the same asconduit 10, but is provided with a different configuration of frictionand/or sealing material 122 on an outer surface 120 s.

The expandable conduit 120 is provided with a pre-expanded portion 120 ein which an expander device (e.g. expander device 16) and/or aninflatable device (e.g. device 14) may be located whilst the conduit 120is run into a borehole or the like. It should be noted that the expanderdevice need not be located in the conduit 120 whilst it is being runinto the borehole, and can be located in the conduit 120 once it is inplace.

As shown in FIG. 5, the expandable conduit 120 is provided with thefriction and/or sealing material 122 at at least one location. Thefriction and/or sealing material 122 is applied to the outer surface 120s of the conduit 120 at axially spaced apart locations, typically spacedfrom one another by around 12 inches (approximately 305 mm).

The friction and/or sealing material 122 is best shown in FIGS. 6 a and6 b. The friction and/or sealing material 122 is in the form of azigzag. In this embodiment, the friction and/or sealing material 122comprises a single (preferably annular) band of rubber that is, forexample, of 90 durometers hardness and is about 2.5 inches(approximately 28 mm) wide by around 0.12 inches (approximately 3 mm)deep.

To provide a zigzag pattern and hence increase the strength of the gripand/or seal that the formation 150 provides in use, a number of slots124 a, 124 b (e.g. 20) are milled into the band of rubber. The slots 124a, 124 b are typically in the order of 0.2 inches (approximately 5 mm)wide by around 2 inches (approximately 50 mm) long.

To create the zigzag pattern, the slots 124 a are milled at around 20circumferentially spaced-apart locations, with around 18° between eachalong one edge 122 a of the band. The process is then repeated bymilling another 20 slots 124 b on the other side 122 b of the band, theslots 124 b on side 122 b being circumferentially offset by 9° from theslots 124 a on the other side 122 a.

In use, the friction and/or sealing material 122 is applied to the outersurface 120 s of the (unexpanded) expandable conduit 120. It should benoted that the configuration, number and spacing of the friction and/orsealing material. 122 can be chosen to suit the particular application.

It should be noted that forces applied to the conduit 10, 120 e.g. bysubsequent movement of the conduit 10, 120 that is by pushing or pullingon the conduit 10, 120 for example, will be mainly transferred to thecasing 12 via the anchor point and not through the inflatable device 14.This is advantageous as it reduces the risk of damage to the inflatabledevice 14. Additionally, this also reduces the risk of damage to thecasing 12 that may have occurred where a conventional slip is used.Also, conventional slips may lose their grip on the casing 12 wheredamage ensues or the casing 12 is weak. Transferring substantially allof the forces directly to the casing 12 via the anchor point obviatesthese disadvantages.

The expander device 16 can then be pulled through the expandable conduit10, 120 to radially expand the conduit 10, 120 as shown in FIG. 1 c. Theexpander device 16 can be propelled through the conduit 10, 120 in anyconventional manner. In FIG. 1, the expander device 16 is pulled throughthe conduit 10, 120 using a string 20 that is attached to the expanderdevice 16 in any conventional manner.

In the embodiment shown in FIG. 1, the expander device 16 istelescopically coupled to the inflatable device 14 using a telescopiccoupling, generally indicated at 22. Coupling 22 comprises one or moretelescopically coupled members 24 that are attached to the inflatabledevice 14. As the expander device 16 is pulled upwards, the telescopiccoupling 22 extends a certain distance, say 10 feet (approximately 3meters), at which point the telescopic member(s) 24 are fully extended.At this point, the inflatable balloon-type portion 14 b is automaticallydeflated and further upward movement of the expander device 16 causesthe inflatable device 14 also to move upward, as shown in FIG. 1 d.

It should be noted that the inflatable device 14 is no longer requiredto anchor the conduit 10, 120 to the casing 12 as the expanded conduit10 (FIGS. 1 c and 1 d) secure the (expanded and unexpanded) conduit 10,120 to the casing 12. The friction and/or sealing material 100, 122 isused to enhance the grip of the conduit 10, 120 on the casing 12 in use,and can also provide a seal in an annulus created between the conduit10, 120 and the casing 12.

The expander device 16 is continually pulled upwards towards the surfaceuntil the expandable conduit 10, 120 is fully expanded to contact thecasing 12. Thereafter, the inflatable device 14 and the expander device16 may be removed from the expandable conduit 10, 120 and/or the casing12 at the surface.

Anchoring and expanding the expandable conduit 10, 120 in this way hasseveral advantages. With the embodiment shown in FIG. 1, it is possibleto deploy a control line or coiled tubing to control operation of theinflatable device 14 and any other apparatus located in the borehole,and a control line, wireline or coiled tubing may be used to propel orpull the expander device 16. With the embodiment shown in FIG. 1, thereis no pressure exposure to the surrounding formation and no rig isrequired. With the inflatable device 14 configured as an annular ring 14r, substantially full bore access is still possible.

It should be noted that the method described with reference to FIG. 1 isintended to expand the expandable conduit 10, 120 in a single pass ofthe expander device 16 through the expandable conduit 10, 120, butmultiple passes and/or expansions are possible.

Referring to FIG. 2, there is shown in sequence (FIGS. 2 a to 2 d)successive stages of hanging an expandable conduit 30 off a casing 32(ie tying back a liner), the expandable conduit 30 typically comprisingan expandable liner and being used to line or case a lower portion of aborehole 34, the borehole 34 typically being drilled to facilitate therecovery of hydrocarbons. The lower portion of the borehole 34 has notbeen lined/cased, wherein the upper portion of the borehole 34 has beenlined with an existing casing or liner 36.

In the embodiment shown in FIG. 2, the expandable conduit 30 is providedwith a friction and/or sealing material 38 on an outer surface thereof.The function of the friction and/or sealing material 38 is to provide a(friction and/or sealing) coupling between the expandable conduit 30 andthe existing liner or casing 36. The friction and/or sealing material 38may also provide a seal between the lower (unlined) and upper (lined)portions of the borehole 34 The friction and/or sealing material maycomprise, for example, any suitable type of rubber or other resilientmaterials. For example, the friction and/or sealing material 38 can beconfigured in a similar way to the friction and/or sealing material 100,122 described above with reference to FIGS. 4 to 6.

Additionally, the conduit 30 may be provided with friction and/orsealing material (e.g. material 100, 122) at a lower end 30 l of theconduit 30 to enhance the anchoring effect at this portion of theconduit. Additionally, the friction and/or sealing material can beprovided at various spaced-apart locations along the length of theconduit 30 to enhance the coupling between the conduit 30 and theborehole 34 or casing. 36.

Referring to FIG. 2, an inflatable device 40, that has an expanderdevice 42 releasably attached thereto, is positioned within theexpandable conduit 30 before the conduit 30 is inserted into theborehole 34. The conduit 30 is provided with an expandable portion ofcasing or liner 44, portion 44 being provided with a plurality oflongitudinal slots 48. The portion 44 may be located at a lower end 30 lof the conduit 30 or may be integral therewith.

Referring to FIG. 2 a, the conduit 30 with the inflatable device 40 andexpander device 42 releasably attached at or near a lower end thereof,is run into the borehole 34 to the required setting depth. As can beseen in FIG. 2 a, a lower end 30 l of the conduit 30 is radiallyexpanded (indicated generally at 50) to allow the expander device 42 tobe located therein. It will be appreciated that although FIGS. 2 a to 2d show the inflatable device 40 and expander device 42 located at ornear the lower end 30 l of the conduit 30, the inflatable device 40and/or the expander device 42 may also be located at or near an upperend of the conduit 30. In this case, the expander device 42 is propelleddownwardly using, for example, the weight of a string, fluid pressure orany other conventional method.

The inflatable device 40 may be of any suitable configuration, but istypically a device that has an inflatable annular balloon-type portion40 b that is mounted on an annular ring 40 r. The annular ring 40 rallows a string, wireline or the like to be passed through theinflatable device 40 as required. This is particularly advantageouswhere; the inflatable device 40 is positioned at the upper end of theconduit 30.

Referring to FIG. 2 b, the inflatable device 40 is inflated to expandthe inflatable annular balloon-type portion 40 b. As the balloon-typeportion 40 b expands, the expandable portion 44 of conduit 30 alsoexpands. As can be seen in FIG. 2 b, the longitudinal slots 48 widen asthe portion 44 expands. Portion 44 acts as an anchor for the casing 30and is expanded until it contacts the borehole 34, as shown in FIG. 2 b.This contact between portion 44 and the borehole 34 provides an anchorpoint and/or a seal between the expandable conduit 30 (to which portion44 is attached or integral therewith) and the borehole 34.

As with the previous embodiment, the expander device 42 is then pulledthrough the expandable conduit 30 to radially expand the conduit 30, asshown in FIG. 2 c. The expander device 42 can be propelled through theconduit 30 in any conventional manner. In FIG. 2, the expander device 42is pulled through the conduit 30 using a drill pipe or string 52 that isattached to the expander device 42 in any conventional manner.

As the expander device 42 is pulled upwards, the upward movement thereofis stopped after a predetermined time or distance, at which point theexpander device 42 is lowered until a coupling between the expanderdevice 42 and the inflatable device 40 latches. As with the previousembodiments, the inflatable annular balloon-type portion 40 b isautomatically deflated and further upward movement of the expanderdevice 42 causes the inflatable device 40 also to move upward, as shownin FIG. 2 d. It should be noted that the upward movement of the expanderdevice 42 should only be stopped once a sufficient length of conduit 30has been expanded to provide a sufficient anchor.

It should also be noted that the portion 44 is no longer required toanchor the conduit 30 to the borehole 34 as the expanded conduit 30(FIGS. 2 c and 2 d) secures the conduit 30 to the borehole 34. Thefriction and/or sealing material (where used) can help to provide areliable anchor for the conduit 30 whilst it is being expanded and alsowhen in use.

The expander device 42 is continually pulled upwards until the conduit30 is fully expanded, as shown in FIG. 2 d Thereafter, the inflatabledevice 40 and the expander device 42 may be removed from the expandableconduit 30 and the borehole at the surface. As shown in FIG. 2 d, theconduit 30 expands whereby the friction and/or sealing material 38contacts the casing 36. This provides a tie back to the casing 36 andoptionally a seal between the upper (lined) portion of the wellbore andthe lower (lined) borehole 34, depending upon the composition of thematerial 38.

With the embodiment shown in FIG. 2, there is no pressure exposure tothe formation, full bore access is still possible, the conduit 30 may beexpanded in a single pass (multiple passes possible) and it may be usedto anchor and set in an open hole. Additionally, it provides a tie backto the casing 36 in a single pass of the expander device 42. It shouldbe noted that the method described with reference to FIG. 2 is intendedto tie back the casing in a single pass, but multiple passes and/orexpansions are possible.

It should also be noted that successive lengths of expandable conduitmay be coupled to casings or liners thereabove using the same method.Thus, the method(s) described herein may be used to line or case aborehole without the use of cement.

Referring to FIG. 3, there is shown in sequence (FIGS. 3 a to 3 d)successive stages of anchoring an expandable conduit 80 to a casing 82provided in a borehole (not shown), the borehole typically being drilledto facilitate the recovery of hydrocarbons.

An inflatable device 84 is releasably attached to a lower end 80 l ofthe expandable conduit 80 before the conduit 80 is inserted into thecasing 82. The expander device 86 is located within the lower end 80 lof the conduit 80, the lower end 80 l being expanded to accommodate theexpander device 86. Similar to the previous embodiment, the inflatabledevice 84 has the expander device 86 releasably coupled thereto via acoupling 88. Otherwise, the inflatable device 84 and the expander device86 are substantially the same as the previous embodiments.

Referring to FIG. 3 a, the casing 80 with the inflatable device 84attached thereto and the expander device 86 located therein is run intothe hole to the required setting depth. It will be appreciated thatalthough FIGS. 3 a to 3 d show the inflatable device 84 releasablyattached to the lower end 80 l of the conduit 80, the inflatable device84 may be releasably attached at or near an upper end of the conduit 80.

The inflatable device 84 may be of any suitable configuration, but istypically a device that has an inflatable annular balloon-type portion84 b that is mounted on an annular ring 84 r. The annular ring 84 rallows a string, wireline or the like to be passed through theinflatable device 84 as required. This is particularly advantageouswhere the inflatable device 84 and/or the expander device 86 arepositioned at the upper end of the conduit 80.

Referring to FIG. 3 b, the inflatable device 84 is inflated to expandthe inflatable annular balloon-type portion 84 b. As the balloon-typeportion 84 b expands, it contacts the casing 82, thus providing ananchor between the conduit 80 and the casing 82. This contact betweenthe balloon-type portion 84 b and the casing 82 provides an anchor pointand/or a seal between the conduit 80 and the casing 82.

It should be noted that in this embodiment, the forces applied to theconduit 80 by subsequent movement of the conduit 80, that is by pushingor pulling on the conduit 80 for example, will be transferred to thecasing 82 via the inflatable device 84. However, unlike conventionalslips, the inflated balloon-type portion 84 b is less likely to damagethe casing. Additionally, the size of the balloon-type portion 84 b canbe chosen whereby it is sufficiently large so as not to lose its grip onthe casing 82, even when the inflatable device 84 is moved upwardly ordownwardly.

The expander device 86 is pulled through the expandable conduit 80 toradially expand the conduit 80, as shown in FIG. 3 c. The expanderdevice 86 can be propelled through the conduit 80 in any conventionalmanner, as with the previous embodiments.

Also, and as with the previous embodiments, an outer surface 80 s of theconduit 80 can be provided with a friction and/or sealing material. Thefriction and/or sealing material may comprise, for example, any suitabletype of rubber or other resilient materials. For example, the frictionand/or sealing material can be configured in a similar way to thefriction and/or sealing material 100, 122 described above with referenceto FIGS. 4 to 6.

Additionally, the conduit 80 may be provided with friction and/orsealing material (e.g. material 100, 122) at a lower end 80 l of theconduit 80 to enhance the anchoring effect at this portion of theconduit 80. Additionally, the friction and/or sealing material can beprovided at various spaced-apart locations along the length of theconduit 80 to enhance the coupling between the conduit 60 and the casing82.

As the expander device 86 is pulled upwards, the upward movement thereofis stopped after a predetermined time or distance, at which point theexpander device 84 is lowered until the coupling 88 between the expanderdevice 86 and the inflatable device 86 latches. As with the previousembodiments, the inflatable balloon-type portion 84 b is automaticallydeflated and further upward movement of the expander device 86 causesthe inflatable device 84 also to move upward, as shown in FIG. 3 d. Itshould be noted that the upward movement of the expander device 86should only be stopped once a sufficient length of conduit 80 has beenexpanded to provide a sufficient anchor.

The expander device 86 is continually pulled upwards towards the surfaceuntil the conduit 80 is fully expanded to contact the casing 82.Thereafter, the inflatable device 84 and the expander device 86 may beremoved from the borehole at the surface.

Anchoring and expanding the conduit 80 in this way has the sameadvantages as in the previous embodiment, but the FIG. 3 embodiment isdesigned to anchor and set in cased hole rather than open hole.

The method and apparatus described herein may be used for a plurality ofdifferent downhole functions relating to the use of expandable conduit.For example, they may be used where the original liner or casingrequires to be repaired due to damage or the like by overlaying thedamaged portion with a portion of expandable conduit. They may also beused to tie back to the liner or casing, as described herein.

Thus, there is provided in certain embodiments an apparatus and methodof anchoring an expandable conduit to a second conduit. The apparatusand method of certain embodiments provide numerous advantages overconventional mechanical anchoring devices, such as slips, particularlyby reducing the potential damage to conduits that mechanical slips maycause. Certain embodiments of apparatus and methods involve the use ofan inflatable device that can either be a) attached directly at or nearthe top or bottom of the expandable conduit, or b) placed within the topor bottom of the expandable conduit. In a), anchoring forces aregenerated as a result of friction between the inflatable device and thesecond conduit, the forces being passed into the conduit via theinflatable device. In b), anchoring forces are generated by frictionbetween an outer surface of the expandable conduit and the secondconduit, the forces being substantially passed into the second conduitdirectly via the expandable conduit. The outer surface of the expandableconduit may be suitably prepared (ie provided with a friction enhancingmaterial) to increase the strength of the anchor.

Modifications and improvements may be made to the foregoing withoutdeparting from the scope of the present invention.

1. Apparatus for anchoring a first conduit to a second conduit, theapparatus comprising: an inflatable device for engaging with the firstconduit, wherein the inflatable device is inflatable to facilitateanchoring of the first conduit to the second conduit; and an expanderdevice to expand a length of the first conduit.
 2. Apparatus accordingto claim 1, wherein the first conduit is an expandable conduit. 3.Apparatus according to claim 1, wherein the first conduit comprises anytype of expandable conduit that is capable of sustaining deformation. 4.Apparatus according to claim 1, wherein the first conduit is selectedfrom the group of conduits consisting of expandable liner and expandablecasing.
 5. Apparatus according to claim 1, wherein the second conduit isselected from the group of conduits consisting of liner, casing andboreholes.
 6. Apparatus according to claim 1, wherein the expanderdevice is telescopically coupled to the inflatable device, so that whenthe expander device is moved a certain distance, the inflatable deviceis deflated and subsequently moves with the expander.
 7. Apparatusaccording to claim 1, wherein the expander device is releasably attachedto the inflatable device.
 8. Apparatus according to claim 7, wherein theexpander device is releasably attached to the inflatable device using alatch mechanism.
 9. Apparatus according to claim 1, wherein theinflatable device is located within the first conduit.
 10. Apparatusaccording to claim 1, wherein the inflatable device is coupled near anend of the first conduit.
 11. Apparatus according to claim 1, whereinthe inflatable device is inflated to expand the first conduit wherebythe first conduit contacts the second conduit, thereby providing ananchor.
 12. Apparatus according to claim 1, wherein the first conduit isprovided with a slotted portion to facilitate expansion.
 13. Apparatusfor anchoring a first conduit to a second conduit, comprising: aninflatable device for engaging with the first conduit, wherein theinflatable device is inflatable to facilitate anchoring of the firstconduit to the second conduit, and wherein the inflatable devicecomprises an inflatable balloon portion coupled to a ring.
 14. Apparatusfor anchoring a first conduit to a second conduit, comprising: aninflatable device for engaging with the first conduit, wherein theinflatable device is inflatable to facilitate anchoring of the firstconduit to the second conduit, and wherein, on inflation of theinflatable device, a portion thereof directly contacts the secondconduit to provide an anchor.
 15. A method of anchoring a first conduitto a second conduit, comprising: providing the first conduit, anexpander device, and an inflatable device in contact with the firstconduit, running the first conduit and inflatable device into the secondconduit, inflating the inflatable device to facilitate anchoring of thefirst conduit to the second conduit, and expanding a length of the firstconduit with the expander device.
 16. A method of anchoring anexpandable conduit to a second conduit, comprising: the steps ofproviding the expandable conduit, running the expandable conduit intothe second conduit, passing an assembly comprising an inflatable deviceand an expander into the expandable conduit, inflating the inflatabledevice to facilitate anchoring of the expandable conduit to the secondconduit, and expanding a length of the expandable conduit with theexpander device.
 17. A method according to claim 16, wherein the methodfurther includes deflating the inflatable device, removing the expanderdevice from the expandable conduit and removing the inflatable devicefrom the expandable conduit.
 18. A method according to claim 16, whereinthe method further includes attaching the expander device to theinflatable device, deflating the inflatable device, removing theexpander device from the expandable conduit and removing the inflatabledevice from the expandable conduit.
 19. The method according to claim16, wherein the assembly is disposed within the expandable conduitduring the running.
 20. The method according to claim 16, wherein theexpander device of the assembly is disposed within the expandableconduit and the inflatable device is disposed outside the expandableconduit during the running.
 21. A method of anchoring an expandableconduit within a wellbore, comprising: running the expandable conduitinto the wellbore; passing an assembly comprising a pressure actuatedradially expandable device and an expandable device into the expandableconduit; actuating the expandable device to facilitate anchoring of theexpandable conduit in the wellbore, and expanding a length of theexpandable conduit with the expander device.